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| United States Patent |
5,060,759
|
|
Dussourd
, et al.
|
October 29, 1991
|
Compressor oil supply system
Abstract
In order to continuously supply lubricant to compressor bearings
independent of attitude, and under varying gravitational forces, an oil
supply system (10) includes an oil sump (14), a pump (22), and a suction
tube (24). The oil sump (14) is defined at least in part by a pair of
intersecting sump walls (16, 18) each of which may comprise a primary wall
dependent upon instantaneous compressor attitude. The pump (22) is adapted
to supply the compressor with oil (20) while at the same time removing
gases from the oil (20) and expelling the removed gases into the oil sump
(14). Additionally, the suction tube extends from the pump to a strategic
point within the oil sump (14) for drawing oil (20) from the oil sump (14)
to the pump (22) in a manner assisting in priming and repriming during
brief interruptions in the flow of oil (20) from the oil sump (14).
| Inventors:
|
Dussourd; Jules L. (Princeton, NJ);
Miller; Stanley M. (Rockford, IL)
|
| Assignee:
|
Sundstrand Corporation (Rockford, IL)
|
| Appl. No.:
|
508578 |
| Filed:
|
April 13, 1990 |
| Current U.S. Class: |
184/6.2; 184/6.16; 417/68; 418/88; 418/94 |
| Intern'l Class: |
F01M 003/00 |
| Field of Search: |
184/6.2,6.16
417/68,366
418/88,94
|
References Cited
U.S. Patent Documents
| 3877853 | Apr., 1975 | Harlin | 184/6.
|
| 3932063 | Jan., 1976 | Butler | 417/68.
|
| 4391573 | Jul., 1983 | Tanaka et al. | 418/88.
|
| 4610602 | Sep., 1986 | Schmid et al. | 417/68.
|
| 4626176 | Dec., 1986 | Cole | 417/54.
|
| 4712986 | Dec., 1987 | Nissen | 418/94.
|
| 4729728 | Mar., 1988 | Gromoll et al. | 418/88.
|
| 4756672 | Jul., 1988 | Trimborn | 417/68.
|
| 4781542 | Nov., 1988 | Ozu et al. | 184/6.
|
| Foreign Patent Documents |
| 3730685 | Jul., 1988 | DE | 418/94.
|
Primary Examiner: Lazarus; Ira S.
Assistant Examiner: Cariaso; Alan B.
Attorney, Agent or Firm: Wood, Phillips, Mason, Recktenwald & VanSanten
Claims
We claim:
1. An oil supply system for a compressor capable of operating under
different attitudes relative to the gravity field, comprising:
an oil sump defined at least in part by a pair of intersecting sump walls,
each of said sump walls comprising a primary wall dependent upon
instantaneous compressor attitude;
means for supplying said compressor with oil; and
an oil suction tube for drawing oil from said oil sump to said oil
supplying means, said oil suction tube extending from said oil supplying
means to a strategic point said oil sump;
said oil sump being generally L-shaped in axial cross-section and said sump
walls including a generally cylindrical side wall and a generally skewed
end wall, said strategic point within said oil sump to which said oil
suction tube extends being adjacent a point of intersection of said
cylindrical side wall and said generally skewed end wall.
2. The oil supply system of claim 1 wherein said primary wall in an
instantaneous horizontal compressor attitude is said cylindrical side wall
and in an instantaneous vertical compressor attitude is said generally
skewed end wall.
3. The oil supply system of claim 1 wherein said oil supplying means
comprises a pump in communication with said oil sump, said pump including
means for rapidly priming and repriming during brief interruptions in flow
of oil from said oil sump.
4. An oil supply system for a compressor capable of operating under
different attitudes relative to the gravity field, comprising:
an oil sump defined at least in part by a pair of intersecting sump walls,
each of said sump walls comprising a primary wall dependent upon
instantaneous compressor attitude;
means for supplying said compressor with oil; and
an oil suction tube for drawing oil from said oil sump to said oil
supplying means, said oil suction tube extending from said oil supplying
means to a strategic point within said oil sump;
said oil sump being generally L-shaped in axial cross-section and said sump
walls including a generally cylindrical side wall and a generally skewed
end wall, said strategic point within said oil sump to which said oil
suction tube extends being adjacent a point of intersection of said
cylindrical side wall and said generally skewed end wall;
said oil suction tube having at least a first portion extending generally
parallel to said generally skewed end wall and a second portion extending
generally parallel to said cylindrical side wall, said oil suction tube
having a reverse bend portion adjacent said oil supplying means extending
generally parallel to said generally skewed end wall and said first
portion of said oil suction tube.
5. An oil supply system for a compressor capable of operating under
different attitudes relative to the gravity field, comprising:
an oil sump defined at least in part by a pair of intersecting sump walls,
each of said sump walls comprising a primary wall dependent upon
instantaneous compressor attitude;
pump means having a convoluted intake in communication with said oil sump
for supplying said compressor with oil and assisting in priming and
repriming during brief interruptions in flow of oil from said oil sump;
and
an oil suction tube for drawing oil from said oil sump to said convoluted
intake of said pump means, said oil suction tube extending to a strategic
point within said oil sump;
said oil sump being generally L-shaped in axial cross-section and said sump
walls including a generally cylindrical side wall and a generally skewed
dome-shaped end wall, said strategic point within said oil sump to which
said oil suction tube extends being adjacent a point of intersection of
said cylindrical side wall and said generally skewed dome-shaped end wall;
said pump means comprising a liquid ring pump operable with said convoluted
intake to define means for rapidly priming and repriming during brief
interruption in flow of oil from said oil sump.
6. The oil supply system of claim 5 wherein said liquid ring pump has an
inlet port in communication with said oil sump, an outlet port in
communication with said compressor, and a gas vent port in communication
with said oil sump.
7. The oil supply system of claim 6 wherein said liquid ring pump includes
a generally cylindrical pump housing and an impeller assembly, said
impeller assembly being eccentrically mounted within said pump housing for
rotation therewithin.
8. The oil supply system of claim 7 wherein said inlet port and said gas
vent port are radially inwardly of said pump housing and said outlet port
is in said pump housing radially outwardly of said inlet port and said gas
vent port.
9. The oil supply system of 7 wherein said convoluted intake includes a
first portion generally radially of said pump housing, a second portion
generally parallel to said pump housing and a third portion generally
radially of said pump housing.
10. An oil supply system for a compressor capable of operating under
different attitudes relative to the gravity field, comprising:
an oil sump defined at least in part by a pair of intersecting sump walls,
each of said sump walls comprising a primary wall dependent upon
instantaneous compressor attitude;
a pump including means for removing gases from oil and expelling removed
gases into said oil sump; and
an oil suction tube for drawing oil from said oil sump to said pump, said
oil suction tube extending to a strategic point within said oil sump;
said oil sump being generally L-shaped in axial cross-section and said sump
walls including a generally cylindrical side wall and a generally skewed
dome-shaped end wall, said strategic point within said oil sump to which
said oil suction tube extends being adjacent a point of intersection of
said cylindrical side wall and said generally skewed dome-shaped end wall;
said primary wall in an instantaneous horizontal compressor attitude is a
cylindrical side wall and in an instantaneous vertical compressor attitude
being a generally skewed dome-shaped end wall, said oil suction tube
having at least a first portion extending generally parallel to said
generally skewed dome-shaped end wall and a second portion extending
generally parallel to said cylindrical side wall, said oil suction tube
having a reverse bend portion adjacent said pump extending generally
parallel to said generally skewed dome-shaped end wall and said first
portion of said oil suction tube.
11. An oil supply system for a compressor capable of operating under
different attitudes relative to the gravity field, comprising:
an oil sump defined at least in part by a pair of intersecting sump walls,
each of said sump walls comprising a primary wall dependent upon
instantaneous compressor attitude;
a pump including means for removing gases from oil and expelling removed
gases into said oil sump; and
an oil suction tube for drawing oil from said oil sump to said pump, said
oil suction tube extending to a strategic point within said oil sump;
said oil sump being generally L-shaped in axial cross-section and said sump
walls including a generally cylindrical side wall and a generally skewed
dome-shaped end wall, said strategic point within said oil sump to which
said oil suction tube extends being adjacent a point of intersection of
said cylindrical side wall and said generally skewed dome-shaped end wall;
said pump comprising a liquid ring pump operable with said oil suction tube
to define means for rapidly priming and repriming during brief
interruptions in flow of oil from said oil sump, said liquid ring pump
having an inlet port in communication with said oil sump, an outlet port
in communication with said compressor, and a gas vent port in
communication with said oil sump, said liquid ring pump including a
generally cylindrical pump housing and an impeller assembly mounted for
relative eccentric rotational movement within said pump housing.
12. The oil supply system of claim 11 wherein said inlet port and said gas
vent port are radially inwardly of said pump housing and said outlet port
is in said pump housing radially outwardly of said inlet port and said gas
vent port, said inlet port and said gas vent port each comprising
circumferentially spaced generally kidney-shaped openings in an end wall
of said pump housing and said outlet port comprising an opening in a side
wall of said pump housing, said impeller assembly including a central
cylindrical hub having a plurality of impeller blades projecting radially
therefrom.
13. The oil supply system of claim 12 wherein said central hub is mounted
eccentrically within said pump housing to create a liquid ring surface
having a radius encompassing said inlet port and said gas vent port, said
central hub being dimensioned so as to fully expose said inlet port and
said gas vent port within said pump housing.
Description
FIELD OF THE INVENTION
The present invention relates generally to oil supply systems and, more
particularly, an oil supply system for a compressor capable of operating
at different attitudes relative to the prevailing gravity field.
BACKGROUND OF THE INVENTION
In many applications such as airborne units, it is necessary for
compressors to operate at different attitudes, i.e., vertically,
horizontally or even upside down in relation to the prevailing gravity
field. The flexibility of the compressor in these applications is usually
limited by the operation of the associated lubrication system which
requires an oil reservoir designed appropriately to provide a continuous
supply of lubricant to the compressor bearings. When the supply of
lubricant is interrupted as by flight maneuvers, it is important that it
be restarted very rapidly in order to avoid mechanical damage.
One approach of the prior art has been to hermetically encapsulate the
compressor, using a horizontally disposed hollow crank shaft of the type
that is disclosed in U.S. Pat. No. 4,729,728. The source of power for oil
pumping in this case is derived from a jet pump energized by a gaseous
discharge stream from the compressor which is caused to expand in a jet
nozzle thereby creating a suction which draws oil up through a suction
tube and pumps the mixture through the hollow shaft. With this
arrangement, centrifugal forces due to shaft rotation will provide some
degree of separation such that the oil will move radially outward to feed
the bearings and the gas will be discharged into the canister around the
compressor housing.
Unfortunately, the arrangement disclosed in U.S. Pat. No. 4,729,728 will
work best near the design operating point. On the other hand, it will be
mismatched at other points and during start-up. Additionally, it will also
back pressure the compressor under such conditions.
Still further, U.S. Pat. No. 4,729,728 teaches the use of a swiveling and
rotatable suction tube. This tube is inherently designed to move in
accordance with gravitational forces so as to follow the movement of oil
in the reservoir. While of interest, this would not be suitable for
airborne applications wherein weight is a factor.
Specifically, the swiveling and rotatable suction tube must, by definition,
be designed in a manner to cause a weight penalty. This follows from the
fact that a very light suction tube may well not be able to overcome
frictional forces at the pivot point. For this reason, it has remained to
provide an entirely satisfactory oil supply system for a compressor
capable of operation at different attitudes.
The present invention is directed to overcoming one or more of the
foregoing problems and achieving one or more of the resulting objects.
SUMMARY OF THE INVENTION
It is a principal object of the present invention to provide a new and
improved oil supply system for lubricating a compressor. It is a further
object of the present invention to provide an oil supply system for a
compressor capable of operation at different installation attitudes. It is
still another object of the present invention to provide an oil supply
system that is suitable for airborne compressor applications.
In an exemplary embodiment, the oil supply system includes an oil sump
defined at least in part by a pair of intersecting sump walls each of
which may comprise a primary wall dependent upon instantaneous compressor
attitude. The oil supply system also includes a pump for supplying the
compressor with oil while removing gases from oil and expelling removed
gases into the oil sump in a manner wherein the pump assists in priming
and repriming during brief interruptions in the flow of oil from the oil
sump. With this arrangement, a tube is provided which extends from the
pump to a strategic point within the oil sump for delivering oil to the
pump over a range of instantaneous compressor attitudes.
Preferably, the oil sump is generally L-shaped in axial cross-section and
the sump walls include a generally cylindrical side wall and a generally
skewed dome-shaped end wall. The primary wall in an instantaneous
horizontal compressor attitude is then the cylindrical side wall and in an
instantaneous vertical compressor attitude is the generally skewed
dome-shaped end wall. When so configured, the strategic point within the
oil sump to which the oil suction tube extends is adjacent a point of
intersection of the side wall and the end wall.
In one form of the invention, the pump has a convoluted intake in
communication with the oil sump whereby the oil suction tube is adapted to
draw oil from the oil sump to the convoluted intake. The convoluted intake
may include a first portion generally radially of the pump, a second
portion generally parallel to the axis of the pump, and a third portion,
again, generally radially of the pump whereby, independent of the
instantaneous compressor attitude, at least some portion or portions of
the intake will always retain oil for the purpose of priming and repriming
the pump. With this arrangement, a liquid ring pump may be utilized which
includes a generally cylindrical pump housing and an impeller assembly
mounted for relative eccentric rotation within the housing.
In this form of the invention, the oil suction tube will extend from the
oil sump to what amounts to a separate, convoluted intake of the pump,
i.e., the oil suction tube and the convoluted intake are separate
components defining a single, continuous flow path. Alternatively, the oil
suction tube may simply comprise a single elongated tube which feeds
directly into the pump in which case it will have at least a first portion
extending generally parallel to the generally skewed dome-shaped end wall
of the oil sump and a second portion extending generally parallel to the
cylindrical side wall of the oil sump. When configured as a single
elongated tube, the oil suction tube will also have a reverse bend portion
adjacent the pump which extends generally parallel to the generally skewed
dome-shaped end wall and generally parallel to the first portion of the
oil suction tube.
In a highly preferred embodiment, the liquid ring pump is operable with its
oil suction tube in a manner defining means for rapidly priming and
repriming the pump during brief interruptions in the flow of oil from the
oil sump. The liquid ring pump advantageously has an inlet port in
communication with the oil sump, an outlet port in communication with the
compressor, and a gas vent port in communication with the oil sump whereby
the inlet port and the gas vent port are radially inwardly of the pump
housing and the outlet port is in the pump housing radially outwardly of
the inlet port and the gas vent port. With this arrangement, the inlet
port and the gas vent port each comprise circumferentially spaced
generally kidney-shaped openings in an end wall of the pump housing and
the outlet port comprises an opening in a side wall of the pump housing.
Still additionally, the impeller assembly preferably includes a central
cylindrical hub adapted to rotate eccentrically within the pump housing
and having a plurality of impeller blades projecting radially therefrom.
The impeller hub thus rotates about its own axis but the liquid surface
forms a circular path concentric with the pump housing having a radius
encompassing the inlet port and the gas vent port. In this connection, the
central hub is dimensioned so as to fully expose the inlet port and the
gas vent port within the pump housing.
Other objects, advantages and features of the present invention will become
apparent from a consideration of the following specification taken in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of a compressor arrangement having an oil
supply system in accordance with the present invention; and
FIG. 2 is a cross-sectional view of the oil supply system taken on the line
2--2 of FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In the illustration given, and with reference first to FIG. 1, the
reference numeral 10 designates generally an oil supply system for a
compressor 12 capable of operating at different attitudes. The oil supply
system 10 includes an oil sump 14 defined at least in part by a pair of
intersecting sump walls 16 and 18 each of which may comprise a primary
wall dependent upon instantaneous compressor attitude. The oil supply
system 10 also includes means for supplying the compressor with oil 20
such as a pump 22. The oil supply system 10 further includes a tube 24
extending from the pump 22 to a strategic point as at 26 within the oil
sump 14 for delivering oil from the oil sump 14 to the pump 22. As will be
appreciated from FIG. 1, the strategic point as at 26 to which the oil
suction tube 24 extends is adjacent a point of intersection as at 28 of
the sump walls 16 and 18, respectively.
Still referring to FIG. 1, the oil sump 14 is generally L-shaped in axial
cross-section and the sump walls include a generally cylindrical side wall
16 and a generally skewed dome-shaped end wall 18. It will also be
appreciated from FIG. 1 that the primary wall in an instantaneous
horizontal compressor attitude (as shown) is the cylindrical side wall 16
in which case the oil 20 will have a surface as at 20a, and in an
instantaneous vertical compressor attitude (not shown), the primary wall
is the generally skewed dome-shaped end wall 18 in which case the oil 20
will have a surface 20b. By reason of the location of the strategic point
as at 26 to which the oil suction tube 24 extends, the open end 30 of the
tube 24 will be submerged in both a vertical and horizontal attitude.
Moreover, it will be appreciated that the open end 30 of the oil suction
tube 24 will actually be submerged in a wide variety of attitudes. This,
of course, includes attitudes in addition to the horizontal attitude
illustrated and the vertical attitude suggested by the surface 20b of the
oil 20. In this connection, it is important for the dome-shaped end wall
18 to be skewed, as illustrated, because otherwise the low point of the
dome would be on the center line of the compressor 12.
Still referring to FIG. 1, the oil suction tube 24 has at least a first
portion 24a extending generally parallel to the generally skewed
dome-shaped end wall 18 and a second portion 24b extending generally
parallel to the cylindrical side wall 16. It will also be seen that the
oil suction tube 24 has a reverse bend portion 24c adjacent the pump 22
which extends generally parallel to the generally skewed dome-shaped end
wall and generally parallel to the first portion 24a of the oil suction
tube 24. In this manner, it will be appreciated that the pump 22 is in
communication with the oil sump 14, drawing oil 20 from the oil sump 14
through the oil suction tube 24 for lubricating the compressor 12.
In the embodiment illustrated, the first, second and reverse bend portions
24a-24c define a convoluted intake generally designated 32 for the pump
22. The convoluted intake 32 serves to assist in rapidly priming and
repriming the pump 22 during brief interruptions in the flow of oil 20
from the oil sump 14 and where there is a composite tubular structure, as
shown, rather than a single elongated tube, the oil suction tube may be
thought of as comprising a short tube segment 24d extending from the
convoluted intake 32, i.e., from the end 34 remote from the pump 22. With
this arrangement, the short tube segment 24d is adapted to draw oil from
the oil sump 14 to the convoluted intake 32 of the pump 22.
Preferably, the pump 22 is a liquid ring pump capable together with the
convoluted intake 32 to define means for rapidly priming and repriming
during brief interruptions in the flow of oil 20 from the oil sump 14. The
liquid ring pump 22 has an inlet port 34 in communication with the oil
sump 14, an outlet port 36 in communication with the compressor 12, and a
gas vent port 38 in communication with the oil sump 14. In addition, the
liquid ring pump 22 includes a generally cylindrical pump housing 40 and
an impeller assembly generally designated 42 which is mounted
eccentrically within the pump housing 40.
Still referring to FIG. 2, the inlet port 34 and the gas vent port 38 are
radially inwardly of the pump housing 40 and the outlet port 36 is in the
pump housing 40 radially outwardly of the inlet port 34 and the gas vent
port 38. The gas vent port 38, in cooperation with the action of the
impeller assembly 42 as it eccentrically rotates within the pump housing
40, comprises means for removing gases from the oil 20 within the pump 22
and expelling the removed gases back into the oil sump 14. As shown, the
inlet port 34 and the gas vent port 38 each comprise circumferentially
spaced generally kidney-shaped openings in an end wall 44 of the pump
housing 40 and the outlet port 36 comprises an opening in a side wall 46
of the pump housing 40.
As best shown in FIG. 2, the impeller assembly 42 includes a central
cylindrical hub 48 adapted to rotate eccentrically within the pump housing
40 and having a plurality of impeller blades 50 projecting radially
therefrom. The central hub 48 rotates about its own axis but the liquid
surface forms a circular path concentric with the housing (as shown in
phantom lines) having a radius encompassing the inlet port 34 and the gas
vent port 38. Moreover, the central hub 48 is dimensioned so as to fully
expose the inlet port 34 and the gas vent port 38 within the pump housing
40.
Referring once again to FIG. 1, the outlet port 36 is adapted to deliver
oil from the liquid ring pump 22 through a tube 52 to bearings shown as at
54. These bearings as at 54 are for a shaft 56 of the rotary compressor 12
which, for purposes of illustration only, has been shown as a freon
compressor particularly suited for airborne applications. Specifically,
the freon compressor 12 is of a type for refrigeration systems which
provide cooling for an aircraft, i.e., by means of a rolling piston type
compressor.
Still referring to FIG. 1, the compressor 12 is illustrated as being
carried on the shaft 56 between the liquid ring pump 22 and a motor 58.
The motor 58 drives the shaft 56 which, in turn, drives the compressor 12
and the pump 22 which is shown on a shaft extension 60. As will be
appreciated, the details of the compressor 12 and motor 58 are unimportant
to an understanding of the present invention.
In this connection, the oil supply system 10 is well suited for any
compressor capable of operating at different attitudes. Thus, the details
which have been discussed, as well as the other components which have not
been discussed for purposes of clarity and brevity, are merely
representative of one use of the present invention. As a result, the
discussion herein, with the exception of the details of the oil supply
system 10, is for illustration purposes only.
While in the foregoing there has been set forth a preferred embodiment of
the invention, it will be appreciated that the details herein given may be
varied by those skilled in the art without departing from the true spirit
and scope of the appended claims.
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